Assertion:Lowering of vapour pressure is not dependent on the number of species present in the solution.
Reason : Lowering of vapour pressure and relative lowering of vapour pressure are colligative properties

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false
D. If both assertion and reason are false

Explanation

To solve the given question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "Lowering of vapor pressure is not dependent on the number of species present in the solution." This implies that the change in vapor pressure does not rely on how many solute particles are present.

### Step 2: Understand the Reason
The reason states that "Lowering of vapor pressure and relative lowering of vapor pressure are colligative properties." Colligative properties are properties that depend on the number of solute particles in a solution, not on their identity.

### Step 3: Analyze the Assertion
Lowering of vapor pressure occurs when a non-volatile solute is added to a solvent. The extent of lowering of vapor pressure is directly related to the number of solute particles present in the solution. Therefore, the assertion is incorrect because lowering of vapor pressure does depend on the number of solute particles.

### Step 4: Analyze the Reason
Relative lowering of vapor pressure is defined as:
\[ \text{Relative lowering of vapor pressure} = \frac{P_0 - P}{P_0} \]
where \(P_0\) is the vapor pressure of the pure solvent and \(P\) is the vapor pressure of the solution. This relative lowering is indeed a colligative property, as it depends on the mole fraction of the solute, which is a function of the number of solute particles. Thus, the reason is correct in stating that relative lowering of vapor pressure is a colligative property.

### Step 5: Conclusion
Since the assertion is incorrect and the reason is correct, we conclude that both statements are not true. Therefore, the correct answer to the question is that both the assertion and the reason are false.

### Final Answer
Both the assertion and the reason are false.

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